Other version managers might allow fuzzy version matching on the string read
from .ruby-version file, e.g. they might allow "1.9.3" (without patch suffix)
to match the latest Ruby 1.9.3 release. rbenv will not support this, because
such behavior is unpredictable and therefore harmful.

rbenv is installed but things just aren't working for me!

Please search existing issues and open a new one if you can't find any answers. Here's a script that dumps information about your current environment; you can use Gist to paste it online and share the URL to it in your bug report: